Originally Posted by Phamilton

Mentioning smell would have been necessary to make the joke understandable to children or people with weak English skills. Clever folks, like "marginal gains" don't need the extra cues.

Edit: yeah, I think I agree that it would have been better had I placed the hyphen after ass, but it wasn't wrong to not have a hyphen. Again, the problem isn't with the joke construction. It was a decent joke. You're grading the joke on too harsh a scale. It wasn't that bad, and it wasn't intended to be great in the first place. Low hanging fruit. I appreciate "weak-ass curve". That made me chuckle.